Hi Julian, it is very difficult to measure without the deck off but with it on its side about the only measurement I can get is that the pulley mounting bracket is 70mm from the rear of the deck, that is to the rear edge of the bracket, not to the bolt holes. As for the arm on the pulley bracket, that fits in an east/west crossmember towards the rear, it fits in a slot you should be able to see on your Anniversary chassis. If you decided to use the Tractor I think you should be able to set up a chain adjuster similar to the Anniversary one. You don't need to use the small sprocket on the adjuster adjuster, a couple of similar sized sealed bearings on a bolt is all that is needed
